ASF specific FreeRTOS functionality that integrates ASF driver libraries with FreeRTOS services to provide a set of highly efficient peripheral interface functions.
The FreeRTOS ASF functions use the peripheral DMA controller (PDC) to send and receive data with practically no processing overhead, and use the FreeRTOS multi-tasking services to ensure the microcontroller can continue executing application code at all times, even when one thread of execution has to wait for a transmit or receive to complete.
Peripherals can be initialized to execute is standard mode or fully asynchronous mode. In standard mode, the API functions used to transmit to or receive from a peripheral do not return until the entire transmit or receive operation has completed. Other FreeRTOS tasks exeucte while the data transfer is in progress. In fully asynchronous mode, the API functions used to transmit to or receive from a peripheral return immediately, which may be while the data transfer is still in progress - the task calling the transmit or receive function is then notified by FreeRTOS when the data transfer has completed.
The FreeRTOS ASF drivers are supported by an application note, executable examples within the ASF distribution, and example use cases in this documentation set.
The following functions are provided for the USART peripheral
The following functions are provided for the UART peripheral
The following functions are provided for the TWI peripheral
The following functions are provided for the TWIHS peripheral
See freertos_twihs_peripheral_control_quick_start
The following functions are provided for the SPI peripheral
See freertos_spi_peripheral_control_quick_start
Modules | |
| Related Project(s) | |
| In this section you can find all the projects related to the FreeRTOS Peripheral Control. | |
| FreeRTOS UART peripheral | |
| control | |
| FreeRTOS TWI peripheral | |
| control | |
| FreeRTOS USART peripheral | |
| control | |
Data Structures | |
| struct | freertos_peripheral_options |
| Define the behaviour of FreeRTOS ASF read and write functions for a peripheral. More... | |
Macros | |
| #define | USE_RX_ACCESS_MUTEX 0x02 |
| Bit definition used in the options_flags member of a freertos_peripheral_options_t structure passed as a parameter to an initialization function to indicate that reads from the peripheral being initialized must be thread aware. More... | |
| #define | USE_TX_ACCESS_SEM 0x01 |
| Bit definition used in the options_flags member of a freertos_peripheral_options_t structure passed as a parameter to an initialization function to indicate that writes to the peripheral being initialized must be thread aware. More... | |
| #define | WAIT_RX_COMPLETE 0x08 |
| Bit definition used in the options_flags member of a freertos_peripheral_options_t structure passed as a parameter to an initialization function to indicate that a task reading from the peripheral must be held in the FreeRTOS Blocked state until the read has completed. More... | |
| #define | WAIT_TX_COMPLETE 0x04 |
| Bit definition used in the options_flags member of a freertos_peripheral_options_t structure passed as a parameter to an initialization function to indicate that a task writing to the peripheral must be held in the FreeRTOS Blocked state until the write has completed. More... | |
Typedefs | |
| typedef struct freertos_peripheral_options | freertos_peripheral_options_t |
| Define the behaviour of FreeRTOS ASF read and write functions for a peripheral. More... | |
Enumerations | |
| enum | peripheral_operation_mode { USART_RS232 = 0, UART_RS232, SPI_MASTER, TWI_I2C_MASTER, TWIHS_I2C_MASTER, NOT_SUPPORTED } |
| Defines the operating modes that can be specified in a freertos_peripheral_options_t structure. More... | |
| #define USE_RX_ACCESS_MUTEX 0x02 |
Bit definition used in the options_flags member of a freertos_peripheral_options_t structure passed as a parameter to an initialization function to indicate that reads from the peripheral being initialized must be thread aware.
When this bit is set the FreeRTOS peripheral driver will use a mutex (internally within the driver) to ensure only one FreeRTOS task can perform a read from the peripheral at any one time. Examples use cases are provided in the FreeRTOS peripheral control examples that are included in the Atmel ASF distribution, in the application not that accompanies the FreeRTOS peripheral control drivers, and in the quick start references for the FreeRTOS peripheral control initialization functions in this online documentation.
Referenced by create_twi_task(), create_usart_tasks(), freertos_uart_serial_init(), and freertos_usart_serial_init().
| #define USE_TX_ACCESS_SEM 0x01 |
Bit definition used in the options_flags member of a freertos_peripheral_options_t structure passed as a parameter to an initialization function to indicate that writes to the peripheral being initialized must be thread aware.
When this bit is set the FreeRTOS peripheral driver will use a binary semphore (internally within the driver) to ensure only one FreeRTOS task can perform a write to the peripheral at any one time. Examples use cases are provided in the FreeRTOS peripheral control examples that are included in the Atmel ASF distribution, in the application not that accompanies the FreeRTOS peripheral control drivers, and in the quick start references for the FreeRTOS peripheral control initialization functions in this online documentation.
Referenced by create_peripheral_control_semaphores(), create_twi_task(), and create_usart_tasks().
| #define WAIT_RX_COMPLETE 0x08 |
Bit definition used in the options_flags member of a freertos_peripheral_options_t structure passed as a parameter to an initialization function to indicate that a task reading from the peripheral must be held in the FreeRTOS Blocked state until the read has completed.
FreeRTOS peripheral read functions often have two version, one where the function name ends with '_async', and one where the '_async' is omitted. This bit must be clear to use the _async version, and set to use the version where _async omitted. See the documentation for the FreeRTOS peripheral read functions for more information. Examples use cases are provided in the FreeRTOS peripheral control examples that are included in the Atmel ASF distribution, in the application not that accompanies the FreeRTOS peripheral control drivers, and in the quick start references for the FreeRTOS peripheral control initialization functions in this online documentation.
Referenced by create_peripheral_control_semaphores(), and create_twi_task().
| #define WAIT_TX_COMPLETE 0x04 |
Bit definition used in the options_flags member of a freertos_peripheral_options_t structure passed as a parameter to an initialization function to indicate that a task writing to the peripheral must be held in the FreeRTOS Blocked state until the write has completed.
FreeRTOS peripheral write functions often have two version, one where the function name ends with '_async', and one where the '_async' is omitted. This bit must be clear to use the _async version, and set to use the version where _async omitted. See the documentation for the FreeRTOS peripheral write functions for more information. Examples use cases are provided in the FreeRTOS peripheral control examples that are included in the Atmel ASF distribution, in the application not that accompanies the FreeRTOS peripheral control drivers, and in the quick start references for the FreeRTOS peripheral control initialization functions in this online documentation.
Referenced by create_peripheral_control_semaphores(), and create_twi_task().
| typedef struct freertos_peripheral_options freertos_peripheral_options_t |
Define the behaviour of FreeRTOS ASF read and write functions for a peripheral.
Defines the operating modes that can be specified in a freertos_peripheral_options_t structure.
1.8.5